@Tod ********
Thanks for all the advice.
Have reached out to:
1) Thai Embassy Kuala Lumpur - Regarding year-long multi-entry Non-O (ideally they would accept proof of funds in Malaysia)
2) Malaysian Embassy Bangkok - Regarding Affidavit of Income. This may be interesting as I'm technically based out of UAE, but will see what they say first.
Will also speak to:
3) Udon Thani immigration - To see if they have any suggestions/advice.
Also wondering if it's worth considering a Tourist Visa (either SETV/METV) from the Thai Embassy Kuala Lumpur, or if that has the same odds as rolling up to DMK/BKK with a Visa Exempt.